I have been planning my next AR15 carefuly, this one is to be a light/medium walking varmint rifle.

I want a free-floated 20" (probably stainless steel) barrel of medium contour, fluted to reduce weight, a flattop upper with a 2-7x compact scope. No iron sights.  The idea being to have something easy to carry for a long hike and accurate enough for prarrie dogs out to 250 yards. I am willing to give up long shot string rapid fire point of aim stability for a lighter barrel this time.

My last concern is porting the barrel.  This should reduce the flip-up of the barrel, but I really do not want to make it louder (for the shooter) as I will occasionally need to make quick shots without hearing protection.

I had not concidered porting previously, but what do you guys think for this application?

I think its a bad idea, especially when you throw in no "ears".

Porting is usually done to reduce recoil and/or muzzle rise.  The AR has almost no recoil anyway.  Why waste the money?

Thanks for the input, I was pretty much decided against porting and it is good to see agreement.

On a full-auto M16 porting or a muzzle brake  would be beneficial to help control the burst, but I'm a long way from that situation.

The military doesn't seem to need them on FA, I never did.  

There is no question that it helps tame recoil/ muzzle rise, but I would question how much of that exists or how much it is needed an the AR platform.